Duster's crazy new mechanic idea

So every once in a while I think of an idea for a card, and I've started making a "set." I think when it gets big enough, I'll put it on here and have you all help me finish it. But I digress. So I was thinking of a Control Magic type card that I'll call Ransom. While thinking about how I want to do this, I thought of the coolest mofo idea I think I've ever thought of. So here it is...Reverb.

Reverb (When ~this~ comes into play you may choose to lose X life, where X must be less than the life total of the opponent with the lowest life total. At any time they could play an instant, any player may choose to lose X life to destroy ~this~.)
Gain control of enchanted creature.
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I'm not positive about the exact wording, but I think that gets the idea across. I'm thinking of more possibilities for this now, I love it!

Hmm, that could be too powerful for the caster, what about working it like kicker?

Reverb: As an additional cost to cast this spell pay the reverb cost. If the reverb cost has been paid any other player may pay the reverb cost to destroy this permanent.

Now you can have some Reverb costs be X life, some be discard a card, some be sack a critter, some be extra mana, and so forth. You could also use a variant to provide countering of the spell and then it would work on instants and sorceries too:

Reverb-variant (needs a name): ~this~ may not be counterd. Any player may pay the Reverb-variant cost to counter this spell.

If the cost involves only non-blue mana, things can get interesting in how it influences the card. At that point, is it a drawback or a feature?